


A wolf when the autumn moon is bright

by fairychangeling



Category: Thor (Movies)
Genre: Accidental Incest, Adopted Sibling Relationship, Alpha Thor (Marvel), Alpha/Beta/Omega Dynamics, Alpha/Omega, Angst, Asgard, Drabble Sequence, Implied/Referenced Underage Sex, M/M, Mating Cycles/In Heat, Omega Loki (Marvel), POV Third Person, Short
Language: English
Status: Completed
Published: 2019-05-27
Updated: 2019-07-22
Packaged: 2020-03-20 04:44:59
Rating: Mature
Warnings: Underage
Chapters: 5
Words: 2,228
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18985540
Author URL: https://archiveofourown.org/users/fairychangeling/pseuds/fairychangeling
Summary: Thor and Loki are brothers.They should be disgusted by each other's scents, not drawn to each other.





	1. Chapter 1

**Author's Note:**

> There is just not enough A/B/O universe stuff for Thorki.
> 
> This is a short, three part, third party POV set from my tumblr imagining a world in which Thor and Loki find out about Loki's adoption in one of the worst possible ways. I have no plans to write any additional parts. 
> 
> I don't have an idea of set ages, but they're all teenagers, with Thor and friends being towards 17/18-ish and Loki being a few years younger.

Loki could be more helpful.

He could magic himself to somewhere safe. He could call Heimdall to take him home, back to Asgard. 

He could do anything but just stand there, looking sorrowfully at Thor as his brother was pinned beneath his friends. 

“This won’t hold him for long,” Hogun grunted as Thor attempted to buck them off.

“Loki, will you do something!” Sif shouted.

Loki took a step closer and Thor howled; his scrabbling and struggling intensifying.

“Something else!” Sif snarled, delivering a sharp elbow to the back of Thor’s head, knocking him down for a moment. “Or do you want to be ravished by your own brother?”

Loki’s cheeks got very pink, but he still didn't move. His eyes darted nervously from Thor to Sif and then back again. 

It would have been heartening to know Loki was so concerned for Thor, if it wasn't for the fact that Thor could break free at any moment. 

“Thor will be fine, Loki, I promise you!” Volstagg cried cheerfully from his perch on Thor’s back. 

Loki continued to hesitate. His hands twitched nervously at his sides, the way they did before he cast a spell, but it seemed now he was fighting to stop himself reaching out to Thor. 

Sif understood his distress, although she cursed Loki silently for it. He wanted to comfort his brother, to calm him down, but it was Loki's presence that was causing Thor to react this way. Ever since his rut had hit, the only thought in Thor's head had been mounting his little brother, and if his friends had not been there to stop him, it was what he would have done.

If Loki would just leave them, then Thor would calm. 

“Do you really want your first time to be with an Alpha in rut before you’ve even come into season?” Fandral asked, wrestling one of Thor’s legs into submission. “He’d split you in two on his knot!” 

Loki’s eyes grew very wide. His fingers moved nervously, tugging at the hem of his tunic. The movement caught Sif's attention. 

She lifted her head and sniffed the air. Her eyes darkened.

Loki was young, far too young, but they'd all heard of Omegas who presented early and Loki had always been precocious. 

“I wouldn’t be so sure about Loki’s season, Fandral,” she muttered.


	2. Chapter 2

“The King is going to kill us,” Fandral moaned, burying his head in his hands.

Hogun said nothing. He stared at the campfire, one eye swollen half-shut where Thor had caught him a blow as he threw him off in his struggle to get to Loki. 

“This shouldn’t have happened,” Sif muttered from her seat beside Fandral. “They’re brothers. They should be disgusted by each other’s scents.”

It had been the opposite. Once Thor had scented Loki’s heat, he had been unstoppable. He’d had the strength of a berserker. Nothing would keep him from claiming Loki as his own. It was a blessing that he'd carried Loki into one of the tents instead of rutting with him out in the open for Sif and the Warriors Three to see. 

They had been able to hear what was happening, but it had been better than watching Loki's defilement first hand. 

Huddled around the campfire, they'd tended their wounds and avoided each other's eye until finally it was over and there had been blissful silence. 

“The Queen is going to kill us,” Fandral wept.

“How often has Thor reminded us to keep a close eye on Loki? How often has he worried about strange Alphas sniffing around Loki, and then he goes and does this!” Sif continued, her mouth twisting angrily.

Thor had always been so protective of Loki, so concerned that some undeserving Alpha would pounce on him at the first hint of his heat. 

Sif wondered now if he had only been concerned someone else would get there first. It was an uncharitable thought, but she did not feel like being charitable when Thor had given her new scars in his struggle to free himself and mount his brother. 

“Thor will kill us!” Fandral wailed.

“And Loki! Loki said he would never spread his legs for any Alpha!” Sif said, stabbing at the ground angrily.

Loki had been as much as slave to his passions as Thor. He’d thrown himself into Thor’s arms, all thoughts of resistance gone from his mind s soon as his brother charged towards him. He'd wanted to be taken. 

The sounds that he made would have caused a whore to blush. 

They made Sif's cheeks redden as she remembered. She'd imagined she knew just how deep Thor had buried his cock into his little brother from Loki's cries. 

“Loki will kill us and it will hurt!” Fandral sniffed. 

“Come now,” Volstagg said cheerfully. He settled down beside the pair, the only one who seemed unfazed and unhurt. “It is not so bad.”

Sif looked at him in disbelief. 

How could he not understand what this meant for the Kingdom? For them all? This wasn't some roll in the hay with a beta that could be forgotten once Thor's rut was over. 

The repercussions of this would be felt for centuries. 

“Not so bad? Our older prince has just claimed the younger as his mate!”


	3. Chapter 3

“What’s wrong with us?”

Frigga didn’t know what to say. 

She let Loki lay his head in her lap, let him weep into her skirts, stroking her fingers through his dark curls, trying to soothe him as best she could. She let magic slip from her fingers, but Loki was too distraught to allow her to heal him. Unconsciously, he repelled her, his own magic working overtime to protect him as Loki tore himself apart, searching for answers and laying the blame at his own door. 

“We’re brothers! I don’t understand how this could have happened.”

He looked up at her, his lashes wet with tears and Frigga kept her face placid as she stared back.

She had told Odin that they should be careful. She had warned him that with Loki’s first season soon approaching they should discuss Loki’s adoption with both their sons, but her husband had scoffed at her fears. 

He didn’t see the closeness they had, didn’t see the danger. 

Thor had been showing off, performing displays of strength designed to impress his potential mate. Loki had been coy, keeping Thor on his toes, but giving just enough encouragement to coax his brother on and make his willingness known. 

It was a mating ritual Frigga had seen a hundred times over and she had seen the danger.

She never would have allowed them to go off adventuring together if it had been her choice alone, but her husband had overruled her. 

Frigga pushed Loki’s hair away from his neck, ignoring her son’s whimper, and looked at the dark, fresh bite that marred his pale skin. 

Loki was mated to Thor now and there was nothing any of them could do to change that.

**Notes for the Chapter:**

> So, I decided to add an additional chapter because I think it would be interesting to have Odin's POV after this one from Frigga.


	4. Chapter 4

“I await your sentence, father. Whatever punishment you decide, I know I deserve it for what I have done.” 

Thor knelt before his father’s throne, his head bowed, as if awaiting the swing of an ax.

Odin gazed at him sadly. 

His proud, golden son, kneeling like a condemned man. 

It should not be this way. 

“What have you done?” 

Thor didn’t raise his head. For all the composure he portrayed, he was frightened.

“I defiled Loki,” he said, the words strained, Thor forcing them out through gritted teeth.

Odin sat back in his throne and regarded Thor glumly.

His son thought he was in the wrong, that he had forced himself upon Loki, when the reports Odin had heard painted a rather different picture of the situation. 

Loki had remained, even when told to leave, and tortured Thor until the temptation became too great for him to resist.

Thor was an Alpha and there were some instincts that no amount of civilizing could erase. 

Omegas knew that and they used it to their advantage. 

Loki would not be the first, nor the last, Omega to let himself be mounted as a means to an end. 

What Loki’s plot had been, why it had been necessary to bind himself to Thor, Odin did not yet know, but he laid the blame for this squarely at Loki’s door. 

He was an Omega. He should have stayed at home, been dutiful and protected his virtue, instead of accepting an invitation to a hunting trip with a group of Alphas. 

“I have been told that Loki was willing.”

That made Thor look up.

His eyes went wide, his mouth working useless as he floundered to respond. Evidently, he had not considered that it was Loki who had seduced him.

It was vexing to think this could have been avoided if only Odin had not shown mercy.

If he had not taken that little cuckoo into his nest, then none of this would have happened. 

Thor was meant for great things. He was meant to mate with a Queen who would bring him new realms, gold and jewels. He was meant to breed strong pups, ensuring the future of Asgard’s line.

He wasn’t supposed to tie himself forever to a Jotun runt, especially not one who had been raised as his brother.

Something would need to be done, but what it would be, Odin did not yet know. 

It was almost impossible to break a mating bond once it had been created. 

Thor’s floundering was now giving way to reckless panic. 

“Punish me! Loki is innocent in this! I was the one who could not control myself!” 

Odin sighed.

“Thor, stop your theatrics,” he commanded. “Loki is no innocent. He is Jotun. They are never innocent.”

That rendered Thor silent. 

It much improved Odin’s mood.

**Notes for the Chapter:**

> To everyone who guessed Odin would be a big bag of dicks, you were right.


	5. Chapter 5

**Notes for the Chapter:**

> The end! Finally!
> 
> So, I moved house in the middle of writing this and it just completely exhausted me so it took a while for this final chapter to be finished but here it is. I hope you all enjoy.

Thor found Loki in his brother’s bedroom.

It looked as if a whirlwind had hit; clothing was strewn across the floor and over the bed.The neatly ordered bookshelves had been ransacked, discarded books littered the floor. A trunk stood open, half-filled and Loki knelt in front of it, carefully folding clothes with a small pile of books already nestled in the bottom of the trunk. 

Loki was packing.

Loki was leaving.

Thor’s stomach lurched unpleasantly.

“Loki,” he said, announcing his presence, uncertain if Loki would want him there after everything that had happened. 

“I’m going,” Loki said, not looking up at him. He continued his packing, turned away from Thor. “We might be able to break the bond. I’ll go to Jotunheim and I’ll...”

The mention of the land of the ice giants caught Thor’s attention. 

“You know then?” he asked, interrupting his brother. 

“That I’m Jotun?” Loki’s breath caught for a moment, but then he continued as if unaffected. “Yes, mother told me. It makes sense. It explains why father has always favoured you over me and why we...how we could…”

Loki stopped, his voice dying away. 

He trembled. 

For all he had tried to put up a brave front, he could hold it together no longer. 

To be Jotun, to be their most hated enemy, to be blamed for corrupting Thor and causing this whole mess - Loki could not bear those indignities without effect, no matter how well he lied. 

Thor could not stand it. 

He reached for Loki, pulling him up, pulling him close, Loki’s back to his chest, an echo of how Thor had taken him in his rut. Even as Loki stiffened, Thor wrapped his arms around him, fearful that Loki would vanish from his sight the moment he let go. 

“Don’t,” he said softly. “Don’t leave me.”

Loki relaxed into his arms. 

Whatever he had been expecting from his brother, it clearly wasn’t Thor begging for him to stay. 

“If I don’t go, we won’t be able to break the bond,” he said.

Thor nodded. 

He pressed his face into Loki’s hair, scenting him.

“Then let’s not break it,” he murmured.

“Thor, that is madness,” Loki said, although he sounded pleased rather than scolding.

“If you leave, I will follow you to Jotunheim. I will track you wherever you go, Loki,” Thor found his voice growing rougher as he spoke, closer to a growl than civilised speech and Loki shivered in his arms. “You are my mate and I will not be parted from you.”

“You want this then? You want to be mated to a Jotun foundling?” Loki asked sharply. 

“I wanted to be mated to you when I thought you my brother in blood,” Thor said.

Loki made a noise of approval and turned in Thor’s arms, facing him.

He tossed his head, hair falling away from his face, and bared his neck; the fresh mating bite drawing Thor’s eye.

Loki was his. His mate. Whatever form he took, whoever he was, that was an unquestionable truth. 

He and Loki were bound together and nothing could break that. They were two halves of a whole. 

“Father won’t like this,” Loki murmured, bringing his own arms up to wrap around Thor’s neck.

“Then he should not have left us alone,” Thor reasoned. “No Alpha could resist you, Loki. I did not even try.”

Loki closed his eyes, an ecstatic expression crossing his face.

“My mate, my alpha,” he sighed.

“Yes,” Thor said, hauling Loki closer so he could kiss him. “All yours.”


End file.
